Leaf spring



CCL 24, 19750 F. T. RowLAND ETAL 2,527,453

LEAF SPRINGv Filed July 24, 1946 2 Sheets-Sheet l F. T. ROWLAND EI'AL LEAF SPRING ATTORNEYS Patented Oct. 24, 1950 UNITED STATES PATENT OFFICE LEAF SPRING Frederick T. Rowland, Emsworth, and Willard F. Perdue, New Castle, Pa., assignors to Standard Steel Spring Company, Coraopolis, Pa., a corporation of Pennsylvania Application July 24, 1946, Serial No. 685,854

10 Claims. l

This invention relates to leaf springs. In order to keep the bending stresses low, particularly in the main spring leaf, it has been necessary to use thin leaves. The use of a thin maintleaf reduces the strength of the main leaf eyes which are used for fastening the spring to the frame of a Vehicle.

The present invention provides a construction in which the strength of the spring at the eyes is increased and in which the spring is prevented fronti" collapsing in the event of failure of the main leaf at any point. Thus if there is failure of the main leaf at any point, the spring will continue to function as a unit until the broken mai leaf can be replaced.

In the accompanying drawings which illustrate two embodiments of my invention, i

Figure l is a partial vertical longitudinal elevation of the leaf spring; V

Figure 2 is a horizontal longitudinal section taken on the line II-II of Figure 3;

Figure 3 is an enlarged partial longitudinal vertical section through the center of the spring;

Figure 4 is a partial longitudinal side elevation of a modied form of spring;

Figure 5 is a horizontal longitudinal section taken on the line V-V of Figure 6; and

Figure 6 is an enlarged partial side elevation of the spring shown in Figure 4.

Referring first to the embodiment shown in Figures 1 through 3, the spring comprises a main leaf I having at each end an eye 2 by means of which the spring can be pivoted to the frame of a vehicle. The main leaf I extends continuously from end to end and has an ey'e 2 at each end although for convenience only a portion of the entire spring has been shown. Located underneath the main leaf I is a wrapper leaf designated generally by the reference numeral3. vThe wrapper leaf is made up of two separate sections 4 and 5. An eye 6 is formed at the outer end of each of the wrapper leaf sections 4 and 5,these eyes 6 acting to reinforce the leyes 2 of the main leaf I. The inner end of each of the wrapper leaf sections 4 and 5 is reduced in horizontal sections to form a neck 'I and an enlarged head 8. A locking plate designated generally by the reference numeral 9 is located between the inner ends of the wrapper leaf sections 4 and 5. "Ihe locking plate 9 is provided with an opening III which receives a center bolt II passing through the whole spring assembly. The head 8 of each of the wrapper leaf sections 4 and 5 is received in 'a recess I2 formed in the lock-ing plate. The recesses lf2 are made suinciently long in a directionendwis'e or the spring heads 8 in the recesses in the normal operation of the spring such that the heads 8 do not contact either with the Walls I3 of the recess or with the ears I4 lof the locking plate. In other words, during the normal operation of the spring, relative endwise movement of the heads 8 with respect to the locking plate takes place due to the diiference in deflection between the main leaf I and the wrapper leaf sections 4 and 5 .but the locking plate does not actually act to lock the wrapper leaf sections l and 5. However, if the main leaf I should fail at any point the locking plate comes into operation and prevents collapsing of the spring. If the main leaf I fails at the left-hand side of the center bolt II, the head 8 of the wrapper leaf section 4 will move to the left, this movement being limited by contact of the head 8 with vthe ears I4. Similarly, if the main leaf I fails at any point to the right of the center bolt I I, the wrapper leaf section 5 will move to the right until its head 8 will contact with the ears I4 of the locking plate. In either case the spring will not collapse but will continue to function thus preventing injury to other parts of the vehicle such as axle, drive shaft and steering mechanism, until the broken main leaf I can be replaced by a new leaf.

A rebound plate I5 is located above the main leaf I and several reinforcing leaves I6 are located below the locking plate 9 and the wrapper leaf sections 4 and 5. Accordingly, the wrapper leaf sections 4 and 5 slide between the main leaf I and the uppermost one of the reinforcing leaves I6. Free sliding movement of the wrapper leaf sections 4 and 5 is facilitated by making the locking plate 9 somewhat thicker than the wrapper leaf sections 4 and 5 so as to provide a space Il as shown in Figure 3. In the embodiment of the spring which is shown, lthere are ten reinforcing leaves I5 but the number of such leaves maybe varied in accordance with the desired characteristics of the spring.

Referring now to the embodiment shown in i Figures 4, 5 and 6, the arrangement is generally 2| of the main leaf. The inner end of the wrapper leaf section 23 is provided with a reduced neck portion 26 and an enlarged head 2l. The head 2l is received in a recess 28 formed in the inner end of the wrapper leaf section 24, the recess 28 being sufficiently long to allow limited relative endwise motion of the head in the recess. The wrapper leaf section 2li is provided with ears 29 which limit movementl of the head '21 upon failure of the main leaf 20.

In order to provide free sliding movement of the wrapper leaf sections 23 and 24 between the main leaf 20 and the uppermost reinforcing leaf 30, the wrapper leaf sections 23 and 24 are provided with slots 3l in each of which a freely movable button or roller 32 is received. The buttons 32 are not connected to any other part but are simply received in the slots 3|. A washer 33 fits around the center bolt Sli. The buttons 32 are slightly longer than the thickness of the wrapper leaf sections 23 and 213 so that they provide spaces 35 between the wrapper leaf sections and the main leaf 20 and the uppermost one of the reinforcing leaves 30. The head 21 of the wrapper leaf section 23 is provided with a slot 36 in which the center bolt 34 is located thereby providing for endwise movement of the wrapper leaf section 23. A rebound plate 3l is located above the main leaf 20.

In the normal operation of the spring, the wrapper leaf sections 23 and 24 have endwise movement suicient to compensate for the difference in deection between the main leaf and the wrapper leaf sections but the wrapper leaf sections are not actually locked together. However, in the event of failure of the main leaf 20 at any point, the ears 23 limit the movement of the head '21 so that the spring will continue to function without collapsing until the broken main leaf can be replaced.

From the above description it can be seen that our invention provides an arrangement wherein the eyes of the main leaf are strengthened so that there is less likelihood of failure at the eyes. Furthermore, in the event of failure of the main leaf at any point, the spring will continue to function as a whole until the broken main leaf can be replaced.

The invention is not limited to the preferred embodiments but may be otherwise embodied or practiced within the scope of the following claims.

We claim:

l. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, a locking plate located between the inner ends of the wrapper leaf sections, said locking plate allowing limited endwise movement of the innei` ends of the wrapper leaf sections relative Yto each other during normal operation of the spring but positively limiting end wise movement of each of said inner ends upon failure of the main leaf at any point.

2. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, the inner end of each wrapper leaf section having a neck and an enlarged head, a locking plate located between the inner ends of the wrapper leaf sections, the locking plate having a pair of recesses each adapted to receive the head of a wrapper leaf section and allow limited relative movement during normal operation of the spring but positively limiting movement upon failure of the main leaf at any point.

3. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, the inner end of each wrapper leaf section having a neck and an enlarged head, a locking plate located between the inner ends of the wrapper leaf sections, the locking plate having a pair of recesses each adapted to receive the head of a wrapper leaf section and allow limited relative movement during normal operation of the spring, the locking plate having means cooperating with the head of each wrapper leaf section for positively limiting movement of the heads upon failure of the main leaf at any point.

4. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper--leaf sections being slidably disposed between the main leaf and reinforcing leaf and locked to each other, one of said wrapper leaf sections having a neck and an enlarged head adjacent its inner end, the other of said wrapper leaf sections having adjacent its inner end a recess adapted to receive the head of said rst mentioned wrapper leaf section and allow limited relative movement during normal operation of the spring but positively limiting movement upon failure of the main leaf at any point.

5. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf and locked to each other so as to allow limited endwise movement of the inner ends of the wrapper leaf sections relative to each other during normal operation of the spring but positively limiting endwise movement of each of said inner ends upon failure of the main leaf at any point, each of the wrapper leaf sections having a longitudinal slot adjacent its inner end and a spacing member freely slidable in each slot, said spacing members being longer than the thickness of the wrapper leaf sections.

6. In a leaf springy having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, and means located entirely between the main leaf and the reinforcing leaf for positively limiting endwise movement of ea'ch of said inner ends away from the other upon failure of the main leaf at any point.

'7. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, and means located entirely between the main leaf and the reinforcing leaf for positively limiting endwise movement of each of said inner ends away from the other upon failure of the main leaf at any point, said means comprising interengaging portions.

8. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf,I the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, and means located entirely between the main leaf and the reinforcing leaf for positively limiting endwise movement of each of said inner ends away from the other upon failure of the main leaf at any point, said means comprising at least one head and at least one pair of ears engaging said head.

9. In a leaf spring having a reinforcing leaf; a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, and means located entirely between the main leaf and the reinforcing leaf for positively limiting endwise movement of each of said inner ends away from the other upon :z

failure of the main leaf at any point, said means comprising interengaging portions formed on said inner ends.

10. In a leaf spring having a reinforcing leaf;

a main leaf having an eye at each end, a pair of wrapper leaf sections having their outer ends provided with eyes which reinforce the eyes of the main leaf, the inner ends of the wrapper leaf sections being slidably disposed between the main leaf and reinforcing leaf, and means located entirely between the main leaf and the reinforcing leaf for positively limiting endwise movement of ea'ch of said inner ends away from the other upon failure of the main leaf at any point, said means comprising a locking plate located between the inner ends of the wrapper leaf sections and engaging each of said inner ends.

FREDERICK T. ROWLAND.

WILLARD F. PERDUE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,623,422 Lovejoy Apr. 5, 1927 1,814,682 Frost July 14, 1931 1,900,841 Nilsson Mar. 7, 1933 1,907,912 Wallace May 9, 1933 2,041,159 Wallace May 19, 1936 2,358,852 Dow Sept. 26, 1944 2,422,718 Dath June 24, 1947 FOREIGN PATENTS Number Country Date 640,317 France Mar. 26, 1925 

